Horizontal furnace for continuous annealing is a relatively common heating furnace, which is divided into several zones in a travel direction of strips in the furnace, so as to control furnace temperature in sub-zones. The accuracy of the measurement of furnace temperature affects the quality and performance of products, so the precision of furnace temperature is extremely important to the performance of the product, the reduction in the precision of furnace temperature directly causes the disqualification in the performance of the product. Because the power of the burner is designed to be relatively high in normal temperature controlling system, which induces relatively high thermal lag and thermal inertia in temperature adjustment, thereby making the curve of the furnace temperature oscillate with a constant amplitude when in stable state, and making the transit time long when in unstable state. These will severely affect the performance and the yield of the product. A conventional method for controlling furnace temperature is dual crossing PID control, which controls the furnace temperature by the proportion between coal gas and air as well as the diversion between the respective proportions. This controlling method is good to systems in which the thermal lag is relatively low. However, the thermal lag and thermal inertia in an annealing furnace is normally relatively high, so that the difficulty in furnace temperature control is relatively high. Also, as to PID controlling method, there is a requirement for pursuing quick response, and another requirement for pursuing stability. If the quick response is desired, the transit time may be shortened, but overshooting will be larger, thereby making the furnace temperature hard to be stabilized. If the stability is desired, the precision of furnace temperature is better, but the transit time of furnace temperature is certainly very long. Thus, it will put control into a dilemma. Furthermore, PID control is after all a stable adjusting method, it can not estimate the incoming material and the change in temperature setting values in advance, and it does not have many adjusting means to the lag in unstable state, the adjustment effect is not good as well. It is necessary to carry out a feed forward control so as to compensate for the lag control in unstable state.